52 terms

Chapter 7- Genetics and Probablility

the branch of biology that studies the ways in which hereditary info is transmitted.
Hereditary Info
responsible for traits (inherited characteristics) of an individual
the mathematical science that predicts the chance that a certain event may occur
transmission of genes from one generation to the next
known as the "father of genetics". He first tested DNA of pea plants and made rules about genetics
monohybrid cross
a cross between 2 individuals who are different for the same trait offspring called monohybrids
dihybrid cross
a cross between 2 individuals who are different for the same trait. offspring are called dihybrids
law of dominance
in a hybrid, the dominant trait is expressed over the recessive when paired together
law of ind. assortment
pair of genes separate independently of one another to form gametes. All possible genes may occur TtYy- TY Ty Yt ty
law of segregation (meiosis)
two alleles of a gene are segregated during gamete formation. so a gamete only carries one of each gene
when geneticists collect and grow baby cells, match the chromosome pairs and look for genetic abnormalities
Sutton and bovers
discovered and wrote chromosome theory after reading and understanding Mendel's work
test cross
when an ind. has the dominant trait and wants to find what genotype it is, they cross themselves with the recessive genotype and look at their offspring to see what their genotype is
a way to test the fetus for abnormalities by inserting a needle through the uteran wall into the amniotic sack where the baby's cells are
cell division during which 2 sister chromatids fail to separate, causing abnormal gametes
down's syndrome
trisomy 21. occurs when nondisjunction causes the egg to carry both chromosomes and is then fertilized by another chromosome on the 21st pair. Causes child to have mental retardation, short stature do to retarded physical development, short stubby legs, hand, abnormally large face and possible congenital heart formations
turner's syndrome
when the individual has 45 chromosomes instead of 46 because it doesnt have a Y This happens when an egg does not contain an X chromosome and is fertilized by an X bearing sperm. These people are usually sterile and sexually underdeveloped, short, below average IQ and abnormalities in skin and skeleton
Kleinfelters syndrome
XXY. the egg was double the number of chromosomes and was fertilized by a Y bearing chromosome. causes extra tall people, usually die early. sexually underdeveloped.
Thomas Morgan
He won a nobel prize for his work with genetics. he studied fruit flies and discovered X-linked traits
fruit flies
x-linked traits
traits only carried by the female X chromosome ex. red green colorblindness and hemophilia
women who have one of their chromosomes marked with the disease
Sickle-cell anemia
is when the blood cells are shaped like a sickle, causing them to not carry as much oxygen to the body. example of codominance because heterozygous people for sickle-cell anemia have both full and sickle cells
Phenylketonuria (PKU)
a person does not have the ability to break down phenylalinine and that lessens the production of melanin
recessive disorder in autosomes where the person cannot break down fatty acids and they accumulate in the brain, causing mental problems.
when you have more than one set of chromosomes. common in plants because it makes them strong. lethal in humans, rare in animals.
gene linkage
genes that travel together during gamete formation
gene mapping
marking the order in which the genes are placed on a chromosome
sex determination
being XX or XY depending on which sperm fertilizes your egg
when there is only one chromosome in a pair
when there is three chromosomes in a pair
an x-linked disease where the blood cannot clot itself
an x-linked disease where one cannot see colors clearly
when a nucleotide is deleted from the sequence, example of frameshift mutations
when a nucleotide is added to the sequence
when a segment of a chromosome detaches itself and flips itself around, messing up the sequence.
when a segment of a chromosome detaches itself and moves to another homologous pair
polygenic (multiple gene) inheritance
when more than one family gene affects the final outcome
cystic fibrosis
when there are no chloride ions and the chloride makes the water in one's body get thick and mucus-like, clogging up respiratory system and digestive system!!!!
chorionic villus sampling
genetic testing where a sample is taken from the baby's chorion (like a pre-placenta) which contains the baby's cells
the use of high frequency sound waves to monitor the baby's growth and appearance while in the womb
when a small camera is placed in the woman's VAGINA!!! and is used to see the baby directly in the womb and can also have a sample taken from it or something
sex influenced traits
having certain traits more common for males and females
sex limited traits
controlled by autosomal genes that can be only found in the sex. ex. making of female and male reproductive organs
jumping genes
when a gene on a chromosome moves from one point to another on the same chromosome
they cause mutations
point mutations
are when a nucleotide is replaced with another nucelotide
frameshift mutations
additions and deletions in the sequence. If this mutation is a deletion, it causes everything to move over
Huntington's disease
it affects the nervous system. symptoms include slow loss of brain function, uncontrollable movements and emotional disturbances
Super Female
XXX. When an egg having two chromosomes is fertilized by an X-bearing sperm. These XXX females have a tendency towards learning disabilities, most have no apparent physical abnormalities
Edward's Syndrome
Trisomy 18. results from an extra chromosome in the 18th pair autosomes. they usually die, have a small chin, a long head, and their fingers are permanently flexed
fetal blood sampling
when blood is drawn directly from the baby in the womb and is used to test for genetic problems